Different syntheses of prostaglandins are reviewed by Corey, Ann. N.Y. Acad. Sci., 180 (1971) 24. The 7-oxa-prostaglandins are discussed by Fried, et al., Ann. N.Y. Acad. Sci., 180 (1971) 38. Other publications related to the synthesis of 7-oxa-prostaglandins include: Fried, et al., J. Am. Chem. Soc., 93 (1971) 5594; Fried, et al., Chem. Comm. (1968) 634. The 7-thia prostanoids are disclosed in U.S. Pat. No. 4,175,201 granted Nov. 20, 1979 to Fried, and U.S. Pat. No. 4,180,672 granted Dec. 25, 1979 to Kurozumi, et al.
The effect of a free hydroxyl group on the regio-specificity of the epoxide opening is discussed in Fried, et al., J. Am. Chem. Soc., 94 (1972) 4343.
The catalytic oxidation of olefins to alpha-epoxy alcohols is dealt with by Kaneda, et al., J. Org. Chem. 45 (1980) 3004; Allison, et al., Ind. and Eng. Chem. (Prod. Res. and Dev.) 5 (1966) 166; Lyons, Tetrahedron Lett. 32 (1974) 2737; U.S. Pat. No. 3,259,638, granted July 5, 1966 to Allison. A bimetallic catalyst for this reaction is disclosed in U.S. Pat. No. 4,021,369, granted May 3, 1977 to Lyons.
The preparation of alpha-epoxy alcohols via catalytic rearrangement of hydroperoxides is discussed by Mercier, et al., Chem. Phys. Lipids 12 (1974) 232. The use of singlet oxygen in the reaction of olefins to hydroperoxides is disclosed by Kopecky, et al., Can. J. Chem., 43 (1965) 2265.
Although much effort has been made to improve the process of catalytic oxidation of olefins to alpha-epoxy alcohols, the processes reported in the art suffer from low reaction rates, low yields, and poor selectivities. The rearrangement of hydroperoxides is fast, but requires separate preparation of these peroxides and their isolation. The process of this invention is fast, gives high yields and is highly selective. Moreover, the process herein is especially adaptable to a total synthesis of prostaglandin analogues, using cyclopentene as a starting material.